It is known that cyclohexanone 2-carboxamide is a valuable intermediate in the production of herbicides. As such, it is important that the carboxamide be readily available in high yield.
East German Pat. No. 112,987, published May 12, 1975, teaches the preparation of cyclohexanone 2-carboxamide by reaction of one equivalent of urea with 1 to 2 equivalents of cyclohexanone in the presence of an acid catalyst followed by acid hydrolysis. There is no teaching within the East German Patent of pH control during acid hydrolysis or the use of excess cyclohexanone. The utility of the carboxamide as an intermediate for preparation of herbicides is recognized.
Canadian Pat. No. 667,356 describes preparation of a spirolactam. It should be noted that an incorrect structure is assigned to the spirolactam in the Canadian Patent. The lactam is taught to be useful as an oxygen scavenger.
Because of the value of cyclohexanone 2-carboxamide as an intermediate for the preparation of herbicides, a process is needed for the preparation of carboxamide which will maximize product yield. According to the instant invention, such a process has been unexpectedly discovered.